In order to better understand our atmosphere, scientists have divided it into several layers. These layers are divided based on the characteristics of the gases found at that height. Imagine a layered cake. A layered cake is made out of layers of different ingredients. The first layer might be cake mix. On top of that a cook could put a layer of pudding. On top of that layer they perhaps could put another layer of cake mix, followed by a layer of whipped cream, and so forth. Each layer in our atmosphere is referred to as a sphere.

The first layer of the atmosphere is, fortunately, not made out of cake, but rather it is made out of the gases that we breathe everyday. This layer is called the troposphere. The troposphere is the layer that we live in.

The next layer of our atmosphere is called the stratosphere. Above the stratosphere lies the mesosphere, followed by the thermosphere, and finally the exosphere. The mesosphere and thermosphere are often referred to together as the ionosphere because of the way they reflect the ionized energy of the Sun. In order to help scientists identify the border between each of these layers, scientists have given special names to the boundaries between a number of them. The boundary between the troposphere and the stratosphere is referred to as the tropopause. The border between the stratosphere and the mesosphere is called the stratopause. And the line separating the mesosphere from the thermosphere is called the mesopause.